This invention relates in general to layered imaging members, inclusive of flexible members and substantially rigid members, or OPC members, comprised, for example, of a photogenerating layer and a charge transport layer, and wherein the charge transport layer contains certain hindered phenols of the formulas illustrated herein, and which phenols are available as IRGANOX 565™ and CYANOX 2176™, available, for example, from Ciba Chemicals. The aforementioned phenols primarily function as an antioxidant and which antioxidant prevents, or minimizes the charge transport components degradation by exposure to ozone.
More specifically, disclosed herein is an electrophotographic imaging member comprised in sequence of a supporting substrate, a hole blocking layer, an adhesive layer, a photogenerating layer, and a charge transport layer containing charge, especially hole transport components, a polymer binder, the hindered phenols illustrated herein, which phenols can function as an effective anti-ozonant to eliminate or suppress the charge transport polymer binder molecular chain scission to permit the prevention of chain backbone break down into low molecular weight polymer fragments that converts the charge transport layer into a brittle coating layer. Furthermore, in embodiments the illustrated herein are electrophotographic imaging members may also contain a plurality of layers, such as two charge transport layers comprising a first (bottom) charge transport layer, which is in contiguous contact with the photogenerating layer, and a second (top) charge transport layer coated over the first charge transport layer. The bottom charge transport layer can comprise a binary solid solution of a charge transport compound and a polymer binder, whereas the top charge transport layer is comprised of a charge transport compound, a polymer binder, and a hindered phenol of the formulas illustrated herein.
Advantages associated with the imaging members of the present invention, in embodiments, thereof include, for example, the avoidance of or minimal undesirable migration of the hindered phenol to the photogenerating layer to thereby avoid imaging member instability, such as electrical performance degradation, and undesirable electrical characteristics especially on long term cycling of the member; coating of two transport layers in separate passes to, for example, minimize the transport layers thickness variations, which variations can cause image defects referred to as rain drops; minimizing and in embodiments avoiding an increase in the lateral surface conductivity of the member which in turn can cause image degradation, referred to as lateral conductivity migration (LCM), and which disadvantages are minimized or avoided with the members of the present invention.
Processes of imaging, especially xerographic imaging and printing, including digital, are also encompassed by the present invention. More specifically, the layered photoconductive imaging members of the present invention can be selected for a number of different known imaging and printing processes including, for example, electrophotographic imaging processes, especially xerographic imaging and printing processes wherein charged latent images are rendered visible with toner compositions of an appropriate charge polarity. Moreover, the imaging members of this invention are useful in color xerographic applications, particularly high-speed color copying and printing processes, and which members are in embodiments sensitive in the wavelength region of, for example, from about 500 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source.